1. Field of Disclosed Subject Matter
This disclosure relates to systems and methods that provide an ability to produce higher quality Magnetic Ink Character Recognition (MICR) characters on substrates in a potentially more efficient manner using a proposed variable digital offset lithographic image forming architecture.
2. Related Art
Magnetic Ink Character Recognition or MICR is a character recognition technology used primarily by the banking industry to facilitate the processing and clearance of checks and other documents of value. MICR provides a scheme for high speed identification and sorting of MICR printed documents. Conventionally, MICR encoding is provided as a line of characters at the bottom of a check or other voucher-type document. The line of MICR characters typically includes information by which to identify the document, including, for example, a document type indicator, and, when the document is a check, a bank code, a bank account number, a check number, and an amount. Some type of control indicator is also generally included.
The MICR characters are generally imaged or printed separately on a document in one of a number of standardized fonts. The ink used in the printing of the MICR characters is considered a magnetic ink based on an inclusion of a magnetizable solid element in its composition. Iron oxide can be included, for example, as the magnetizable solid element.
MICR printed documents are processed mechanically and electronically through a MICR reader, which may also act as a document sorter according to individual data elements in the read information. The MICR reader reads pertinent information about the check or the other document of value including the amount, the account number, and the other information. Once read, this information is used by the sorter portion of the MICR reader to enable an electronic sort of the read documents for routing purposes. In some MICR readers, the MICR characters are passed over a magnetization portion that magnetizes the MICR ink imaged characters. The characters are then passed over a MICR read head, which may be a device similar to the playback head of a tape recorder. As each character passes over the MICR read head, it produces a unique waveform that can be easily identified by the MICR reader.
The use of MICR allows the characters to be read reliably even if they have been overprinted or obscured by other marks that may have been, for example, separately added to the checks or other documents of value in visual verification and/or other transaction processing steps. An advantage to the use of MICR in these processing and sorting schemes is that error rates experienced in the magnetic scanning of typical checks and other documents of value are significantly smaller than those experienced with automated optical reading and sorting techniques, including those that use optical character recognition.
Currently, MICR documents are typically produced in a multi-step process. The “non-changing” background and formatting images are typically printed using an offset lithographic process. Then, a separate digital printer is used to print the “changing” digital information in the MICR portion of the document. This production scheme of using separate printing steps, often with separate devices, seeks to offset disadvantages in the separate processing techniques that have conventionally made them incompatible in producing the separate images on the MICR documents.
Conventional lithographic and offset lithographic printing techniques use plates that are permanently patterned, and are, therefore, generally considered to be most useful only when printing a same image in long print runs, such as for the background images on the documents of value that are to be overprinted with MICR data that changes from substrate-to-substrate. These conventional processes are generally not considered amenable to creating and printing a new pattern from one page to the next because, according to known methods, removing and replacing of plates, including on a print cylinder, would be required in order to change images.
Based on the above, conventional lithographic techniques cannot accommodate true high speed variable data printing processes in which the images to be printed change from impression to impression, for example, as in the case of digital printing systems. This is among the reasons why the MICR portions of a document are digitally printed separately.
The lithography process is often relied upon because it provides very high quality printing at least in part due to the quality and color gamut of the inks used. Based on their consistent reuse in a process where residual ink on the plate is less of a concern, the lithographic inks tend to be much more viscous as they are loaded with greater amounts of solid components. The inks, which typically have very high color pigment content, often in a range of 20-70% by weight, tend to have comparatively very low cost compared to other inks, toners and many other types of printing or marking materials. This comparatively low cost generates a desire to use the lithographic and offset inks for printing or marking in order to take advantage of the high quality and low cost in a manageable manner. The viscous nature of these inks is not considered a disadvantage based on the lithographic ink delivery and image forming techniques. As indicated above, however, lithographic printing techniques have conventionally not been considered amenable to digital printing as that term is intended to refer to production of images on substrates that are changeable with each subsequent rendering of an image on successive substrates in an image forming process.
Although ink jet printing is amenable to high speed variable digital data image forming, the physical compositions of the jetted inks must be carefully controlled within fairly rigid parameters. Generally, jetted inks cannot be particularly viscous and/or they cannot contain particles over a certain size. Overly viscous ink compositions, or ink compositions having solid particles with larger particle sizes, will tend to easily clog the jets and introduce other issues that adversely affect image forming operations through the ink jetting process supporting the digital printing.
The preparation of jettable inks often involves extensive pulverization of the solid elements, such as the pigments or other solids included in the ink compositions, with, for example, steel shot or in a grinder (high speed media mill), in order that the solid elements are more easily suspended in the liquid thus making them easier to pass in the ink jetting process.
A difficulty arises in the compatibility of the MICR scheme with inks prepared by pulverizing the solid elements. While this is done today to support the requirements of the MICR inks being jettable, certain trade-offs are made in balancing the limitations imposed by the ink jetting digital image forming process and the preferences for composition of MICR components in the inks to effectively implement a MICR image forming scheme. In MICR, it is more preferable to have larger particles of iron oxide or other magnetizable elements in order to distinguish or read the MICR characters using a suitable magnetic image reader. To the extent that MICR can be considered a reflectance process, it is easily understood that, when a larger magnetizable surface is presented to the magnetization portion of the MICR reader, and then to the reader portion, the produced and read magnetic field will be comparatively easier to read in a manner that differentiates the MICR ink image or printed portions of the document.
A desire to form MICR characters with larger particles of magnetizable material, however, conflicts with the practical need in preparing jettable inks to pulverize the solids into as small a size as possible for those constituent elements of the jettable inks. When this concern is combined with a concern that only limited amounts of magnetizable solids can be added to the jettable ink solution without adversely affecting the viscosity of the jettable ink, it becomes clear that producing MICR inks for digital inkjet image forming of the MICR characters on a substrate requires balancing competing limitations that may keep the advantages of MICR from being fully realized and exploited.